New driver for r61505u chip

Hi notro!

Thanks for your great display driver framework!
With it I was able to write a driver for my display in a few hours :)
See my blog if you want to get more infos:
http://lallafa.de/blog/2013/03/watterott-display-on-raspberry-pi/

If you want to include my driver code in your code tree then simply use this pull request...

Cheers,
Chris/lallafa